fec.c

实现一个网卡到内存空间的零拷贝程序

#ifndef final_version
	{
	int	i;
	cbd_t	*bdp;

	printk("Ring data dump: cur_tx %lx%s, dirty_tx %lx cur_rx: %lx\n",
	       (unsigned long)fep->cur_tx, fep->tx_full ? " (full)" : "",
	       (unsigned long)fep->dirty_tx,
	       (unsigned long)fep->cur_rx);

	bdp = fep->tx_bd_base;
	printk(" tx: %u buffers\n",  TX_RING_SIZE);
	for (i = 0 ; i < TX_RING_SIZE; i++) {
		printk("  %08x: %04x %04x %08x\n",
		       (uint) bdp,
		       bdp->cbd_sc,
		       bdp->cbd_datlen,
		       bdp->cbd_bufaddr);
		bdp++;
	}

	bdp = fep->rx_bd_base;
	printk(" rx: %lu buffers\n",  RX_RING_SIZE);
	for (i = 0 ; i < RX_RING_SIZE; i++) {
		printk("  %08x: %04x %04x %08x\n",
		       (uint) bdp,
		       bdp->cbd_sc,
		       bdp->cbd_datlen,
		       bdp->cbd_bufaddr);
		bdp++;
	}
	}
#endif
	if (!fep->tx_full)
		netif_wake_queue(dev);
}

/* The interrupt handler.
 * This is called from the MPC core interrupt.
 */
static	void
fec_enet_interrupt(int irq, void * dev_id, struct pt_regs * regs)
{
	struct	net_device *dev = dev_id;
	volatile fec_t	*fecp;
	uint	int_events;
#ifdef CONFIG_FEC_PACKETHOOK
	struct	fec_enet_private *fep = dev->priv;
	__u32 regval;

	if (fep->ph_regaddr) regval = *fep->ph_regaddr;
#endif
	fecp = (volatile fec_t*)dev->base_addr;

	/* Get the interrupt events that caused us to be here.
	*/
	while ((int_events = fecp->fec_ievent) != 0) {
		fecp->fec_ievent = int_events;
		if ((int_events & (FEC_ENET_HBERR | FEC_ENET_BABR |
				   FEC_ENET_BABT | FEC_ENET_EBERR)) != 0) {
			printk("FEC ERROR %x\n", int_events);
		}

		/* Handle receive event in its own function.
		 */
		if (int_events & FEC_ENET_RXF) {
#ifdef CONFIG_FEC_PACKETHOOK
			fec_enet_rx(dev, regval);
#else
			fec_enet_rx(dev);
#endif
		}

		/* Transmit OK, or non-fatal error. Update the buffer
		   descriptors. FEC handles all errors, we just discover
		   them as part of the transmit process.
		*/
		if (int_events & FEC_ENET_TXF) {
#ifdef CONFIG_FEC_PACKETHOOK
			fec_enet_tx(dev, regval);
#else
			fec_enet_tx(dev);
#endif
		}

		if (int_events & FEC_ENET_MII) {
#ifdef	CONFIG_USE_MDIO
			fec_enet_mii(dev);
#else
printk("%s[%d] %s: unexpected FEC_ENET_MII event\n", __FILE__,__LINE__,__FUNCTION__);
#endif	/* CONFIG_USE_MDIO */
		}

	}
}


static void
#ifdef CONFIG_FEC_PACKETHOOK
fec_enet_tx(struct net_device *dev, __u32 regval)
#else
fec_enet_tx(struct net_device *dev)
#endif
{
	struct	fec_enet_private *fep;
	volatile cbd_t	*bdp;
	struct	sk_buff	*skb;

	fep = dev->priv;
	spin_lock(&fep->lock);
	bdp = fep->dirty_tx;

	while ((bdp->cbd_sc&BD_ENET_TX_READY) == 0) {
		if (bdp == fep->cur_tx && fep->tx_full == 0) break;

		if (bdp->cbd_sc & BD_ENET_TX_LAST) {
			/* Was last buffer of frame: check for errors
			   and deal with skb. */

			skb = fep->tx_skbuff[fep->skb_dirty];
			/* Check for errors. */
			if (bdp->cbd_sc & (BD_ENET_TX_HB | BD_ENET_TX_LC |
					   BD_ENET_TX_RL | BD_ENET_TX_UN |
					   BD_ENET_TX_CSL)) {
				fep->stats.tx_errors++;
				if (bdp->cbd_sc & BD_ENET_TX_HB)  /* No heartbeat */
					fep->stats.tx_heartbeat_errors++;
				if (bdp->cbd_sc & BD_ENET_TX_LC)  /* Late collision */
					fep->stats.tx_window_errors++;
				if (bdp->cbd_sc & BD_ENET_TX_RL)  /* Retrans limit */
					fep->stats.tx_aborted_errors++;
				if (bdp->cbd_sc & BD_ENET_TX_UN)  /* Underrun */
					fep->stats.tx_fifo_errors++;
				if (bdp->cbd_sc & BD_ENET_TX_CSL) /* Carrier lost */
					fep->stats.tx_carrier_errors++;
			} else {
#ifdef CONFIG_FEC_PACKETHOOK
				/* Packet hook ... */
				if (fep->ph_txhandler &&
				    ((struct ethhdr *)skb->data)->h_proto
				    == fep->ph_proto) {
					fep->ph_txhandler((__u8*)skb->data, skb->len,
							  regval, fep->ph_priv);
				}
#endif
				fep->stats.tx_packets++;
			}

			/* Deferred means some collisions occurred during transmit,
			 * but we eventually sent the packet OK.
			 */
			if (bdp->cbd_sc & BD_ENET_TX_DEF)
				fep->stats.collisions++;

			/* Free the sk buffer associated with this last transmit.
			 */
#if 0
printk("TXI: %x %x %x\n", bdp, skb, fep->skb_dirty);
#endif
			dev_kfree_skb_irq (skb/*, FREE_WRITE*/);
			fep->tx_skbuff[fep->skb_dirty] = NULL;
			fep->skb_dirty = (fep->skb_dirty + 1) & TX_RING_MOD_MASK;

		}

		/* Update pointer to next buffer descriptor to be transmitted.
		 */
		if (bdp->cbd_sc & BD_ENET_TX_WRAP)
			bdp = fep->tx_bd_base;
		else
			bdp++;
		fep->tx_ring_len--;
		fep->tx_full = 0;

#ifdef CONFIG_FEC_PACKETHOOK
		/* Re-read register. Not exactly guaranteed to be correct,
		   but... */
		if (fep->ph_regaddr) regval = *fep->ph_regaddr;
#endif
	}

	/* Wake queue if there is enough room in the tx ring */
#ifdef CONFIG_FEC_SUPPORT_SG
	if (fep->tx_ring_len + MAX_SKB_FRAGS < TX_RING_SIZE) {
#else
	if (fep->tx_ring_len < TX_RING_SIZE) {
#endif
		fep->tx_full = 0;
		if (netif_queue_stopped(dev))
			netif_wake_queue(dev);
	}

	fep->dirty_tx = (cbd_t *)bdp;
	spin_unlock(&fep->lock);
}


/* During a receive, the cur_rx points to the current incoming buffer.
 * When we update through the ring, if the next incoming buffer has
 * not been given to the system, we just set the empty indicator,
 * effectively tossing the packet.
 */
static void
#ifdef CONFIG_FEC_PACKETHOOK
fec_enet_rx(struct net_device *dev, __u32 regval)
#else
fec_enet_rx(struct net_device *dev)
#endif
{
	struct	fec_enet_private *fep;
	volatile fec_t	*fecp;
	volatile cbd_t *bdp;
	struct	sk_buff	*skb;
	ushort	pkt_len;
	__u8 *data;

	fep = dev->priv;
	fecp = (volatile fec_t*)dev->base_addr;

	/* First, grab all of the stats for the incoming packet.
	 * These get messed up if we get called due to a busy condition.
	 */
	bdp = fep->cur_rx;

while (!(bdp->cbd_sc & BD_ENET_RX_EMPTY)) {

#ifndef final_version
	/* Since we have allocated space to hold a complete frame,
	 * the last indicator should be set.
	 */
	if ((bdp->cbd_sc & BD_ENET_RX_LAST) == 0)
		printk("FEC ENET: rcv is not +last\n");
#endif

	/* Check for errors. */
	if (bdp->cbd_sc & (BD_ENET_RX_LG | BD_ENET_RX_SH | BD_ENET_RX_NO |
			   BD_ENET_RX_CR | BD_ENET_RX_OV)) {
		fep->stats.rx_errors++;
		if (bdp->cbd_sc & (BD_ENET_RX_LG | BD_ENET_RX_SH)) {
		/* Frame too long or too short. */
			fep->stats.rx_length_errors++;
		}
		if (bdp->cbd_sc & BD_ENET_RX_NO)	/* Frame alignment */
			fep->stats.rx_frame_errors++;
		if (bdp->cbd_sc & BD_ENET_RX_CR)	/* CRC Error */
			fep->stats.rx_crc_errors++;
		if (bdp->cbd_sc & BD_ENET_RX_OV)	/* FIFO overrun */
			fep->stats.rx_crc_errors++;
	}

	/* Report late collisions as a frame error.
	 * On this error, the BD is closed, but we don't know what we
	 * have in the buffer.  So, just drop this frame on the floor.
	 */
	if (bdp->cbd_sc & BD_ENET_RX_CL) {
		fep->stats.rx_errors++;
		fep->stats.rx_frame_errors++;
		goto rx_processing_done;
	}

	/* Process the incoming frame.
	 */
	fep->stats.rx_packets++;
	pkt_len = bdp->cbd_datlen;
	fep->stats.rx_bytes += pkt_len;
	data = (__u8*)__va(bdp->cbd_bufaddr);

#ifdef CONFIG_FEC_PACKETHOOK
	/* Packet hook ... */
	if (fep->ph_rxhandler) {
		if (((struct ethhdr *)data)->h_proto == fep->ph_proto) {
			switch (fep->ph_rxhandler(data, pkt_len, regval,
						  fep->ph_priv)) {
			case 1:
				goto rx_processing_done;
				break;
			case 0:
				break;
			default:
				fep->stats.rx_errors++;
				goto rx_processing_done;
			}
		}
	}

	/* If it wasn't filtered - copy it to an sk buffer. */
#endif

	/* This does 16 byte alignment, exactly what we need.
	 * The packet length includes FCS, but we don't want to
	 * include that when passing upstream as it messes up
	 * bridging applications.
	 */
	skb = dev_alloc_skb(pkt_len-4);

	if (skb == NULL) {
		printk("%s: Memory squeeze, dropping packet.\n", dev->name);
		fep->stats.rx_dropped++;
	} else {
		skb->dev = dev;
		skb_put(skb,pkt_len-4);	/* Make room */
		eth_copy_and_sum(skb,
				 (unsigned char *)__va(bdp->cbd_bufaddr),
				 pkt_len-4, 0);
		skb->protocol=eth_type_trans(skb,dev);
		netif_rx(skb);
	}
  rx_processing_done:

	/* Clear the status flags for this buffer.
	*/
	bdp->cbd_sc &= ~BD_ENET_RX_STATS;

	/* Mark the buffer empty.
	*/
	bdp->cbd_sc |= BD_ENET_RX_EMPTY;

	/* Update BD pointer to next entry.
	*/
	if (bdp->cbd_sc & BD_ENET_RX_WRAP)
		bdp = fep->rx_bd_base;
	else
		bdp++;

#if 1
	/* Doing this here will keep the FEC running while we process
	 * incoming frames.  On a heavily loaded network, we should be
	 * able to keep up at the expense of system resources.
	 */
	fecp->fec_r_des_active = 0x01000000;
#endif
#ifdef CONFIG_FEC_PACKETHOOK
	/* Re-read register. Not exactly guaranteed to be correct,
	   but... */
	if (fep->ph_regaddr) regval = *fep->ph_regaddr;
#endif
   } /* while (!(bdp->cbd_sc & BD_ENET_RX_EMPTY)) */
	fep->cur_rx = (cbd_t *)bdp;

#if 0
	/* Doing this here will allow us to process all frames in the
	 * ring before the FEC is allowed to put more there.  On a heavily
	 * loaded network, some frames may be lost.  Unfortunately, this
	 * increases the interrupt overhead since we can potentially work
	 * our way back to the interrupt return only to come right back
	 * here.
	 */
	fecp->fec_r_des_active = 0x01000000;
#endif
}


#ifdef	CONFIG_USE_MDIO
static void
fec_enet_mii(struct net_device *dev)
{
	struct	fec_enet_private *fep;
	volatile fec_t	*ep;
	mii_list_t	*mip;
	uint		mii_reg;

	fep = (struct fec_enet_private *)dev->priv;
	ep = &(((immap_t *)IMAP_ADDR)->im_cpm.cp_fec);
	mii_reg = ep->fec_mii_data;

	if ((mip = mii_head) == NULL) {
		printk("MII and no head!\n");
		return;
	}

	if (mip->mii_func != NULL)
		(*(mip->mii_func))(mii_reg, dev);

	mii_head = mip->mii_next;
	mip->mii_next = mii_free;
	mii_free = mip;

	if ((mip = mii_head) != NULL) {
		ep->fec_mii_data = mip->mii_regval;
	}
}

static int
mii_queue(struct net_device *dev, int regval, void (*func)(uint, struct net_device *))
{
	struct fec_enet_private *fep;
	unsigned long	flags;
	mii_list_t	*mip;
	int		retval;

	/* Add PHY address to register command.
	*/
	fep = dev->priv;
	regval |= fep->phy_addr << 23;

	retval = 0;

	save_flags(flags);
	cli();

	if ((mip = mii_free) != NULL) {
		mii_free = mip->mii_next;
		mip->mii_regval = regval;
		mip->mii_func = func;
		mip->mii_next = NULL;
		if (mii_head) {
			mii_tail->mii_next = mip;
			mii_tail = mip;
		} else {
			mii_head = mii_tail = mip;
			(&(((immap_t *)IMAP_ADDR)->im_cpm.cp_fec))->fec_mii_data = regval;
		}
	} else {
		retval = 1;
	}

	restore_flags(flags);

	return(retval);
}

static void mii_do_cmd(struct net_device *dev, const phy_cmd_t *c)
{
	int k;

	if(!c)
		return;

	for(k = 0; (c+k)->mii_data != mk_mii_end; k++)
		mii_queue(dev, (c+k)->mii_data, (c+k)->funct);
}

static void mii_parse_sr(uint mii_reg, struct net_device *dev)
{
	struct fec_enet_private *fep = dev->priv;
	volatile uint *s = &(fep->phy_status);

	*s &= ~(PHY_STAT_LINK | PHY_STAT_FAULT | PHY_STAT_ANC);

	if (mii_reg & 0x0004)
		*s |= PHY_STAT_LINK;
	if (mii_reg & 0x0010)
		*s |= PHY_STAT_FAULT;
	if (mii_reg & 0x0020)
		*s |= PHY_STAT_ANC;
}

static void mii_parse_cr(uint mii_reg, struct net_device *dev)
{
	struct fec_enet_private *fep = dev->priv;
	volatile uint *s = &(fep->phy_status);

	*s &= ~(PHY_CONF_ANE | PHY_CONF_LOOP);

	if (mii_reg & 0x1000)
		*s |= PHY_CONF_ANE;
	if (mii_reg & 0x4000)
		*s |= PHY_CONF_LOOP;
}

static void mii_parse_anar(uint mii_reg, struct net_device *dev)
{
	struct fec_enet_private *fep = dev->priv;
	volatile uint *s = &(fep->phy_status);

	*s &= ~(PHY_CONF_SPMASK);

	if (mii_reg & 0x0020)
		*s |= PHY_CONF_10HDX;
	if (mii_reg & 0x0040)
		*s |= PHY_CONF_10FDX;
	if (mii_reg & 0x0080)
		*s |= PHY_CONF_100HDX;
	if (mii_reg & 0x00100)
		*s |= PHY_CONF_100FDX;
}
#if 0
static void mii_disp_reg(uint mii_reg, struct net_device *dev)
{
	printk("reg %u = 0x%04x\n", (mii_reg >> 18) & 0x1f, mii_reg & 0xffff);
}
#endif

/* ------------------------------------------------------------------------- */
/* The Level one LXT970 is used by many boards				     */

#ifdef CONFIG_FEC_LXT970

#define MII_LXT970_MIRROR    16  /* Mirror register           */
#define MII_LXT970_IER       17  /* Interrupt Enable Register */
#define MII_LXT970_ISR       18  /* Interrupt Status Register */
#define MII_LXT970_CONFIG    19  /* Configuration Register    */
#define MII_LXT970_CSR       20  /* Chip Status Register      */

static void mii_parse_lxt970_csr(uint mii_reg, struct net_device *dev)
{
	struct fec_enet_private *fep = dev->priv;
	volatile uint *s = &(fep->phy_status);

	*s &= ~(PHY_STAT_SPMASK);